Java 获取 Unix时间戳

unix时间戳是从1970年1月1日（UTC/GMT的午夜）开始所经过的秒数，不考虑闰秒。

在大多数的UNIX系统中UNIX时间戳存储为32位，这样会引发2038年问题。

但是，因为需求是需要int类型的UNIX时间戳。 开始的时候我是这样设计的。

/**
	 * 获取当前事件Unxi 时间戳
	 * @return
	 */
	public static int getUnixTimeStamp(){
		long rest=System.currentTimeMillis()/1000L;
		return (int)rest;
	}

从新封装了一些方法。如下稳定性就好很多了。

 package com.xuanyuan.utils;

 public class TimeUtils {

       /**
      * Constant that contains the amount of milliseconds in a second
      */
     static final long ONE_SECOND = 1000L;

     /**
      * Converts milliseconds to seconds
      * @param timeInMillis
      * @return The equivalent time in seconds
      */
     public static int toSecs(long timeInMillis) {
         // Rounding the result to the ceiling, otherwise a
         // System.currentTimeInMillis that happens right before a new Element
         // instantiation will be seen as 'later' than the actual creation time
         return (int)Math.ceil((double)timeInMillis / ONE_SECOND);
     }

     /**
      * Converts seconds to milliseconds, with a precision of 1 second
      * @param timeInSecs the time in seconds
      * @return The equivalent time in milliseconds
      */
     public static long toMillis(int timeInSecs) {
         return timeInSecs * ONE_SECOND;
     }

     /**
      * Converts a long seconds value to an int seconds value and takes into account overflow
      * from the downcast by switching to Integer.MAX_VALUE.
      * @param seconds Long value
      * @return Same int value unless long > Integer.MAX_VALUE in which case MAX_VALUE is returned
      */
     public static int convertTimeToInt(long seconds) {
         if (seconds > Integer.MAX_VALUE) {
             return Integer.MAX_VALUE;
         } else {
             return (int) seconds;
         }
     }

 }